The present invention relates to mobile ground borne or aerial imaging systems and, more particularly, generally to a mobile groundborne and/or airborne pod based system for providing and exploiting accurately geo-referenced spectral digital imagery in real-time and near real-time.
It is an accepted perspective for ongoing experimental projects involving imaging spectrometersxe2x80x94operating across all ranges of the electromagnetic spectrumxe2x80x94that hyperspectral and ultraspectral imaging will play a key role in remote sensing. Hyperspectral imaging involves the use of imaging spectrometers to remotely measure two dimensional variations in surface spectral reflectivity. Like hyperspectral imaging technology, ultraspectral utilizes more channels and at narrower channel widths to offer an even finer measurement of spectral data. Hyperspectral and ultraspectral may be referred to as spectral sensors herein throughout. Hyperspectral imaging systems have been developed for locating materials of economic and military value and accurately determining the spatial location and extent of such materials. An example of such a hyperspectral system can be seen in U.S. Pat. No. 6,008,492 by Slater et al. titled xe2x80x9cHyperspectral Imaging Method And Apparatusxe2x80x9d (which is commonly owned by the assignee of the present application). An example of another airborne imaging spectrometer can also be seen in U.S. Pat. No. 5,276,321 by Chang et al. titled xe2x80x9cAirborne Multiband Imaging Spectrometer.xe2x80x9d Hyperspectral instruments operating in the various portions of the electromagnetic spectrum, however, have been large, cumbersome, expensive, and not very practical for field operations due to their fixed nadir (a constant orthogonal look angle relative to an aircraft underside or other vehicle position). Scanning mirrors and global positioning systems (xe2x80x9cGPSxe2x80x9d) have also been used to assist with this imaging. These systems, however, remain limited in reaching desired imaging areas and in providing high imaging quality for many different types of applications. Accordingly, there is still a need to enhance imaging by providing additional flexibility and stabilization in such hyperspectral and ultraspectral sensing systems.
With the foregoing in mind, the present invention advantageously provides a system and methods which utilize select narrow-band, flexible combination narrow-band and/or wideband hyperspectral imaging sensors integrated within a gyrostabilized and steerable gimbal mounted assembly, which permits three axis steering of the sensor, as well as inertial three axis stabilization. In order to apply the advantages of spectral technology in the areas of operation where it is most needed, and in a manner commensurate with the data collection spectral sensors in these areas, the present invention provides a consolidated sensor and gimbal assembly which can operate on a variety of light platforms and provides exploitable information from a practical perspective in a more cost effective basis. The operational level of training skill required is also reduced by the present invention from that of typically a post graduate scientist level to that of someone with only a few weeks of training, such as a technician. The system and methods advantageously provide the ability to respond to terrorist planning and actions with potential chemical/biological weapons in a more rapid and effective manner.
The present invention further provides a two or three dimensional display of the data that can be outputted to a computer monitor display, as controlled from a compact onboard flight station which includes integrated power, data, and computer processing equipment, as well as necessary mechanical interfaces to operate the motion of the steerable gimbal to which the sensors are mounted. A video or other imaging camera is also preferably mounted and co-boresighted within the housing of the steerable gimbal which also has a spectral sensor positioned therein to augment the field of view in order to provide the operator with additional wide frame visual reference for broad area target acquisition and tracking. The camera can also advantageously include auto-track capability for maintaining spectral target tracking once lock on a target area is achieved. The operator can advantageously steer the gimbal via a joystick controller and has control over zoom, pan, and tilt functions to enable exact point fixing and holding within a very small area, as low as within one meter or less, to thereby provide additional information on an exact target within the wide area context. This can be important, for example, for obtaining the ambient physical, tactical and spectral conditions supporting assessment of target spectral data and attempting to quantify false alarms and false negatives.
The spectral sensor is preferably controlled via a separate computer interface for adjusting spectral band settings (number and width) and associated frame rates. When combined with a global positioning system (xe2x80x9cGPSxe2x80x9d) or a differential global positioning system (xe2x80x9cDGPSxe2x80x9d) data, the information from the sensor is displayed with position data to provide extremely precise three dimensional location target specifics relating to the position, shape and mechanical dynamics of the targets, such as moving vapor clouds or surface moving vehicles. Strong consideration has been placed on utilizing low cost commercial and/or off-the-shelf hardware as major components in order to ensure maximum performance, minimum cost, and high reliability. Key emphasis has also been placed on tactical style mobility to obtain maximum value of spectral data in a manner beneficial to military and commercial users.
Off-nadir capability of the present invention provides the ability to increase the cross-sectional area, adjust and continuously fine tune the look angle, and acquire additional physical perspective by the instrument to acquire a more representative sample set from the target. It also allows a more efficient and larger target aspect perspective, thereby permitting selected dedication of onboard processor resources in a more effective manner for fine discrimination once a target has been identified and requires additional scan information. Steering can be accomplished, for example, via azimuth and elevation servos, as understood by those skilled in the art, resulting in complete polar coordinate system coverage. Missions against targets also can be accomplished by the direct manual control of the instrument operator or through automated software programs which utilize GPS and target grid information to automatically slew the sensor toward the target of interest regardless of day/night conditions or operator direct input. The instrument form factor packaging and relative light weight of about 100 lbs allows operation from a variety of air and ground vehicles.
The present invention advantageously creates a completely self contained and tactically useful broadband or combination of narrow band sensors as part of a consolidated spectral robotic sensing system for airborne and groundborne application. Commercial off the shelf technology can advantageously be employed in a unique manner to ensure low cost and robust and simple operation from smaller and more flexible platforms which is necessary for practical fielding of this innovative technical approach to detect a new class of commercial and military targets in a rapid, reliable and effective manner.